| 摘要 |
PURPOSE:To suppress the autodoping, and to sharpen the concentration gradient between a high-concentration Si layer and a low-concentration Si layer in the growth of an extremely low-concentration Si layer on a high-concentration Si layer, either by using SiCl4 and raising the temperature during the growth or by using first SiH4 and then changing to SiCl4. CONSTITUTION:The first extremely low concentration Si layer (i-layer) is applied to a high-concentration Si substrate at a relatively low temperature in a vapor phase by the hydrogen reduction reaction of SiCl4 to the extent that the autodoping of the layer does not take place. The temperature of the system is raised, and the second extremely low concentration Si layer is applied to the above i-layer by vapor-phase crystal growth. As an alternative method, the first extremely low-concentration Si layer is applied to the substrate 1 in vapor phase by the thermal decomposition of SiH4 in H2 atmosphere, and then the second extremely low-concentration Si layer is applied thereto in vapor phase by the hydrogen reduction reaction of SiCl4. |
